Security of physical localities has always been, and continues to be, a matter of concern for various entities, governmental and private alike.
While there are numerous systems and apparatuses that have been developed to secure land-based installations, systems and apparatuses that may be employed or deployed in marine (i.e., water) environments are less prevalent, primarily due to the difficulties associated with the placement and maintenance of such systems in marine environments.
As detailed below, many marine security apparatuses and systems employ sonar (or equivalent detection systems) to determine if an intruder is approaching or has entered a secure marine perimeter.
While sonar is effective in detecting the approach or entry of intruders into a secure marine perimeter, there are limitations to sonar. Specifically, with respect to small-sized intruders, sonar has detection limitations. This may become a concern if the intruder is a diver or some type of robotic submersible.
There has developed, therefore, a desire for those seeking to secure a marine perimeter for systems that provide reliable intruder detection. In particular, there has developed a desire for perimeter barriers that provide a physical barrier while also providing a capability for automated detection of intrusions and attempted intrusions.
Before providing a summary of the present invention, a summary of some prior art devices is provided below.
U.S. Statutory Invention Registration No. H 2148 describes an underwater net protection system. The system includes a flexible netting 14, extending upwardly from underwater anchor locations 16, that defines an underwater protective zone 10. Penetration attempts, such as a hole 20 in the flexible netting 14, are monitored by a system 18. The bottom portion 19 of the netting 14 is made from a substantially heavier material than the rest of the netting 14 so as to resist or prevent lifting thereof. The netting is made from elongated netting elements 26 that are cross-fastened to one another. The elongated netting elements 26 include a tubular portion 28 that encases the optical fiber signal line 30 and a reinforcement member 29 that extends in parallel with the optic fiber signal line 30. An attempt to cut (or an actual cut through) the netting 14 is detected by the penetration detection system 18. As illustrated in FIG. 1, it appears that the netting 14 is suspended from a ship to protect a dock 12.
U.S. Pat. No. 7,233,544 describes a harbor fence that is used to establish a security perimeter around a ship or other vessel, for example. The harbor fence system 103 includes a number of spars 105, 107, 109 that are connected to one another at the waterline by a cable containing multiple wires and at the top by a thinner top line with at least one wire. The shape of the harbor fence 103 is maintained by moors 111, which includes a floating platform 151 that is anchored by anchors 153, 155. The spar 109 includes an upper section 161, a retractable keel 163, and a counterweight 165. The upper section 161 may include sensors to detect whether the harbor fence 103 is being impacted. The system may also detect a cut in the top line. Alternatively, the harbor fence system 103 may interact with an underwater sonar system 1300 that can detect underwater intruders that attempt to dive beneath the harbor fence system 103.
U.S. Pat. No. 6,681,709 describes a port security barrier system 10 that is designed to stop hostile, high speed, waterborne craft 12 that attempt to enter the area secured by the barrier system 10. The security barrier 10 is made up of several modules 14, each of which is about 50 feet (15.24 m) in length. A mooring system 15 includes mooring buoys 16, mooring lines 18, and mooring anchors 20. When assembled, the barrier 10 provides a continuous, floating wall for the port facility that extends from 1 to 8 feet (30.48 to 243.84 cm) above the water. The barrier system 10 appears to be designed specifically for threats on the water's surface.
U.S. Pat. No. 7,140,599 describes a coupling system and method for marine barriers. Specifically, this patent describes a barrier system that includes a coupler that permits adjacent sections of the barrier system to be stored (in a non-deployed state) in a side-by-side fashion. With respect to FIG. 31, for example, the system includes barrier segments 880 with float pipes 882, net posts 884, and a net system 886. The barrier system 880 also includes a raft module 890 such that a predetermined load may be supported on the platform 894. The barrier system 880 creates a barrier line to prevent ingress of watercraft into a protected zone surrounded by the barrier system 880. The barrier system 880 appears to be directed to threats on the surface of a body of water.
U.S. Pat. No. 7,123,785 is directed to an optic fiber security fence system that includes an optical fiber net woven from an optical fiber wire. A light generator introduces an incident light signal into the optical fiber wire. A light receiver receives an exigent light signal from the optical fiber wire. An optical sensor wire also is provided. The optical sensor wire is connected to the optical fiber wire and is displaced when a force is applied to the optical fiber net. The optical sensor wire receives a patterned incident light signal that is altered upon application of a force to the optical fiber net, thereby producing an altered patterned exigent light signal. The light receiver initiates an alarm either (1) if the exigent light signal from the optical fiber wire terminates, or (2) after comparing the exigent patterned light signal with the incident patterned light signal in the optical sensor wire and establishing a deviation, if the deviation exceeds a predetermined threshold.
U.S. Pat. No. 7,245,810 describes a fiber optic cable fastener that joins fiber optic cable. The fastener includes a first segment having a plurality of grooves to accommodate portions of the fiber optic cables. Raised contoured portions are configured to damage the fiber optic cables if an intruder tampers with the fastener.
U.S. Pat. No. 4,399,430 describes an intruder detection security system including a security fence 2 made from a plurality of elongated members 4, 6, 8, 10, 12, and 14. The elongated members are optical fibers surrounded by or coated with polyvinyl chloride (“PVC”). FIG. 9 of the '430 patent illustrates the cross-section of one of the elongated members, showing the optical fiber 1 loosely housed within a PVC tube 5 reinforced with Kevlar® strength members 3. (Kevlar® is a trademark of the Dupont Company referring to a para-aramid fiber manufactured by that company. According to the information provided by the DuPont Company through its website, http://www.dupont.com/kevlar/whatiskevlar.html, Kevlar® fibers consist of long molecular chains produced from poly-paraphenylene terephthalamide.) The elongated members 4, 6, 8, 10, 12, 14 form a mesh between two upright posts 16, 18. In one embodiment, at each joining point 20 of the elongated members 8, 10, 12, 14, the elongated members 8, 10, 12, 14 are joined together by a steel ferrule 36. The optical fibers 4, 6, 8, 10, 12, 14 are connected between an output control box 22 and an input control box 24. If the amplitude of the signals received by the output control box 22 fall outside a predetermined range, an output signal is transmitted to operate an alarm 34.
U.S. Pat. No. 4,371,869 describes a fence or wall incorporating a fiber-optic wave guide. The security system described in the '869 patent includes a composite strip 1 of bendable material, which is referred to as a carrier strip 2. The carrier strip 2 may be made of steel, for example. A single fiber-optic filament 3 extends within a groove running along the face of the carrier strip 2. The carrier strip 2 probably is coated with a corrosion-resistant layer in the form of a sheathing 4, for example. A light source or laser generator 6 directs light into one end of the fiber-optic filament 3 and a detector 7 receives the light signal at the other end. The detector 7 is connected to a warning device 8. The warning device 8 is activated if a change in the intensity of light exiting the fiber-optic filament 3 falls outside of a predetermined range.
U.S. Pat. No. 4,450,434 describes an apparatus for determining a break in locations in fencing. As described, a cable 4 is strung along a fence 2 and is attached to the fence 2 via support means 6 for is attached to the fence by being interwoven therein). The cable 4 is made of an optical fiber with an electrical transmission line running therealong. In the embodiment illustrated in FIG. 2, the cable 4 is made of two optical fibers 8, 10, which are coated with metalized coatings 12, 14. The coated fibers are separated from one another by the insulating material 16 in which they are embedded. The cable 4 is connected to an LED or laser transmitter 30 at one end and a light receiver 32 at the other end. One end of the transmission line is connected to a pulse generator 34 and a pulse receiver 36. The other end is open-circuited. The optical portion of the cable 4 carries the light signal such that a break in the light signal is detected by the level detector 40, triggering operation of an alarm means 42. The output of the level detector 40 is connected to the input of the electrical pulse generator 34, which generates an electrical pulse that is reflected to the pulse receiver 36. The time delay between the initiation and receipt of the electrical pulse permits the system to establish the location of the break.
U.S. Pat. No. 4,558,308 describes an intrusion warning wire-lattice that comprises a number of single fence sections 1 mounted between box-type posts 2. Each fence section 1 includes solid wires (shown in dashed lines) and a serpentine coil 4 made of a hollow wire (shown in solid lines). The tubular wires encapsulate an electrical or optical conductor 8 that is connected to an alarm system, which is responsive to a break or deformation of the electrical or optical conductor 8.
U.S. Pat. No. 4,829,286 describes a security fence system made up of a taut wire fence made of taut wires 10 strung in a parallel orientation between an anchoring post 12 and a sensor post 14. An optical fiber 17 is threaded serially through a plurality of adjacent sensor posts and is coupled to a signal transceiver 18. A taut wire connection element 34 is connected to the sensor post 14 and to two adjacent taut wires 36. The connection element 34 rotatably connects to the sensor post 14. An optical fiber engagement member 38 connects to the rod 30 so that is also rotates on the sensor post 14. The taut wire connection element 34 and the optical fiber engagement member 38 are connected to one another such that, if the taut wire connection element 34 and the optical fiber engagement member 38 rotate with respect to one another over a long period of time, the optical fiber 42 is not disturbed. As a result, no alarm sounds. However, if the taut wire connection element 34 is rotated rapidly, the optical fiber engagement member 38 also rotates, displacing the optical fiber 42, thereby triggering an alarm.
U.S. Pat. No. 5,530,430 describes a vibration responsive barbed tape security system. The security system is made up of multiple sections of fence barrier 1 that surround an area. The barrier includes a chain link fence 2 and a secondary barrier 4 in the form of a spiral barbed tape. A tube 24 is in contact with each loop of the spiral barbed tape. The tube 24 contains a vibration sensitive fiber optic cable 30 that transmits light in a predictable manner. Any movement or vibration of the tube vibrates the fiber optic cable, triggering an alarm.
UK Patent Application No. GB 2 038 060 describes an intruder alarm that gives an alarm when an intrusion has occurred into a protected area and also gives an alarm when an attempt to breach a protected area is in progress. The intruder alarm includes a network of optical fiber light conductors forming or included in a fence. Light is fed into the ones of the light conductors such that penetration or attempted penetration of the light conductors triggers an alarm.
According to the English translation, Japanese Patent No, JP 3053400 describes a trespasser monitor method that detects whether a trespasser exists and the position of the trespasser by detecting the position of the reflection of an optical pulse from a disconnection point.
Other fence systems that employ an optic fiber sensor include, but are not limited to, U.S. Pat. Nos. 7,488,929, 7,419,140, 7,402,790, 7,385,506, 7,184,907, 7,173,690, 7,135,970, 7,110,625, 7,068,166, and 6,980,108. These fence systems appear to involve only land-based secure perimeters.
U.S. Pat. No. 4,365,239 describes an intrusion warning system for protecting a wall or a fence, in particular a chain link fence, against intrusion (via cutting) or by climbing over same. The system combines a shielded cable 2 with a chain link fence 1. The fence 1 is intended to extend around the perimeter of an area to be protected. The length of the shielded cable 2 may be as long as 1,000 feet (304.8 m) in the described example. The shielded cable 2 is an electrical coaxial cable with an inner conductor surrounded by an outer, shielded conductor with a layer of insulating dielectric material therebetween. In operation, a signal is sent through the coaxial cable. An attempt to break through the fence disrupts the electrical signal, triggering an alarm.
Reference also is made to U.S. Pat. No. 7,339,474, which describes a deflection sensing system that relies on taught, electrified, metal wires to detect an instruction or attempted intrusion.
Concerning optical fibers, reference is made to U.S. Pat. No. 7,590,322, which describes a fiber optic cable with enhanced saltwater performance. The fiber optic cable 100 has a configuration tailored or optimized to inhibit water penetration and water migration down the cable 100. The cable 100 includes water-swellable tape 135 and water-swellable yarn 120 to block migration of fresh water and/or saltwater along the cable 100. The cable includes a jacket 115, a buffer tube 150, and corrugated metal armor 175. Optical fibers 105 are positioned within the water-swellable yarn 120.
It has been found that certain marine environments present enhanced technical challenges when employing an optic fiber security fence in a marine environment. Accordingly, it has been noted that a more robust optic fiber net may present improved security characteristics in a marine environment.
As made apparent by the above-identified prior art, physical security systems fix marine environments that provide automated intrusion detection are not prevalent in the prior art.